Search Results (314)

Fullerenes were modified into fulleramines by the wet chemical method, and then a CoRu/CNB bimetallic catalyst with defect-rich carbon-coated CoRu alloy and Ru NPs anchored on N- and B-doped carbon, promoting full pH hydrogen evolution, was prepared by condensation reflux and pyrolysis. Structural analysis indicates that the carbon layer endows the catalyst with excellent acid/alkali corrosion resistance, and the defect-rich characteristics expose more active sites. This catalyst only requires overpotentials of 21, 33, and 56 mV to drive HER to a current density of 10 mA cm⁻² in alkaline, acidic, and neutral solutions, featuring a rapid kinetic process and a large electrochemically active surface area. The synergistic effect of CoRu alloy and Ru NPs promotes charge redistribution and accelerates electron transfer, enabling CoRu/CNB to exhibit electrochemical activity and stability far exceeding that of commercial Pt/C in 1 M KOH, 0.5 M H₂SO₄, and 1 M PBS media. Full article

The development of metal nanostructures on large-area Gallium Nitride (GaN) surfaces has the potential to enable new, low-cost technologies for III-N semiconductor layer nanostructuring. Self-assembled nanostructures are typically formed through the thermal activation of solid-state dewetting (SSD) in thin metal layers. However, such thermal processing can induce degradation of the metal-GaN material system. This comprehensive study investigated the thermal stability of thin metal films on GaN surfaces, focusing on their morphology and nanostructuring for high-temperature processing. The research expands and systematizes the understanding of the thin metal layers on GaN surface interactions at high temperatures by categorizing metals based on their behaviour: those that exhibit self-assembly, those that catalyze GaN decomposition, and those that remain thermally stable. Depending on the annealing temperature and metal type, varying degrees of GaN layer decomposition were observed, ranging from partial surface modification to significant volumetric degradation of the material. A wide range of metals was investigated: Au, Ag, Pt, Ni, Ru, Mo, Ti, Cr, V, Nb. These materials were selected based on criteria such as high work function and chemical resistance. In this studies metal layers with a target thickness of 10 nm deposited by vacuum evaporation on 2.2 $\mathsf{\mu }$m thick GaN layers grown by metal organic vapor phase epitaxy were applied. The surface morphology and composition were analyzed using AFM, SEM, EDS, and Raman spectroscopy measurement techniques. Full article

Significant efforts have been devoted to discovering novel metal-based complexes with better cytotoxicity and specificity to tumor cells. Within the range of complexes studied for cytotoxic activity, Ru complexes have gained significant attention as one of the most promising classes of compounds offering advantages such as good scaffolds for the construction of new bioactive molecules with a variety of ligands. Ruthenium-based compounds demonstrate efficient penetration into cancer cells and show affinity for DNA binding with antitumor mechanisms, other than those of cisplatin. They were identified as perfect chemotherapeutics for cancer treatment due to their good tolerance by normal cells, negligible toxic effects and stronger activity towards Pt-drug-resistant tumor cell lines. Ru-based complexes may interact with multiple targets and show selective accumulation in cancer cells, which enhances their therapeutic potential. In recent years, the design of polynuclear complexes has aroused considerable interest in drug discovery research. The strategy to incorporate two or more metal centers into one precise molecular structure may result in better cytotoxic activity compared to the mononuclear precursors. That is why ruthenium-based multinuclear anticancer organometallic and complex compounds have attracted lots of attention. The objective of the current review is to highlight the key results obtained in research on ruthenium complexes, presenting the up-to-date advances of multinuclear homometallic ruthenium complexes as promising anticancer candidates. The reported outcomes shed new light on the fundamental biological interactions and antineoplastic modes of action of ruthenium-based complexes and organometallic compounds as well as significant information for the prediction of novel anticancer drugs. Full article

Fullerene-supported single-atom catalysts (SACs) have emerged as a promising class of materials for electrocatalytic overall water splitting, offering a route to reduce reliance on scarce and costly precious metals. This review systematically summarizes recent advances in the design, synthesis, and application of fullerene-based SACs, with an emphasis on their unique structural, electronic, and catalytic properties. The exceptional stability, conductivity, and surface chemistry of fullerenes enable strong interactions with metal atoms, allowing high dispersion and enhanced catalytic performance for both the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Recent studies demonstrate that C₆₀- and C₂₄-based materials, when combined with transition metals such as Pt, Ru, and V, exhibit superior HER/OER activity, bifunctionality, and spin-selective catalytic pathways. The vast structural space of fullerene–metal combinations presents new opportunities, which can be efficiently explored using machine learning and high-throughput simulations. By integrating density functional theory, transition state modeling, and data-driven techniques, this emerging research frontier is paving the way for rational catalyst design. The review concludes by proposing a machine learning-assisted framework to predict and screen high-performance fullerene-based SACs, ultimately accelerating the development of efficient, stable, and scalable electrocatalysts for sustainable hydrogen production. Full article

In recent years CO₂ reforming of methane has attracted great interest as it produces high CO/H₂ ratio syngas suitable for the synthesis of higher hydrocarbons and oxygenated derivatives since it is a way for disposing and recycling two greenhouse gases with high environmental impact, CH₄ and CO₂, and because it is regarded as a potential route to store and transmit energy due to its strong endothermic effect. Along with noble metals, all the group VIII metals except for osmium have been studied for catalytic CO₂ reforming of methane. It was found that the catalytic activity of Ni, though lower than those of Ru and Rh, was higher than the catalytic activities of Pt and Pd. Although noble metals have been proven to be insensitive to coke, the high cost and restricted availability limit their use in this process. It is therefore valuable to develop stable Ni-based catalysts. In this contribution, we show how their activity and coking resistivity are greatly related to the size and dispersion of Ni particles. Well-dispersed Ni nanoparticles were achieved by multistep impregnation on a mesoporous silica support, namely SBA-15, obtained through a sol-gel method, using acetate as a nickel precursor and keeping the Ni loading between 5% and 11%. Significant catalytic activity was obtained at temperatures as low as 450 °C, a temperature well below their deactivation temperature, i.e., 700 °C. For the pre-reduced samples, a CO₂ conversion higher than 99% was obtained at approximately 680 °C. As such, their deactivation by sintering and coke formation was prevented. To the best of our knowledge, no Ni-based catalysts with complete CO₂ conversion at temperatures lower than 800 °C have been reported so far. Full article

The transition to a sustainable chemical industry necessitates efficient valorization of biomass, with polyols serving as versatile, renewable feedstocks. This comprehensive review, focusing on advancements within the last five years, critically analyzes the selective hydrogenolysis of key biomass-derived polyols—including glycerol, erythritol, xylitol, and sorbitol—into valuable diols. Emphasis is placed on the intricate catalytic strategies developed to control C–O bond cleavage, preventing undesired C–C scission and cyclization. The review highlights the design of bifunctional catalysts, often integrating noble metals (e.g., Pt, Ru, Ir) with oxophilic promoters (e.g., Re, W, Sn) on tailored supports (e.g., TiO₂, Nb₂O₅, N-doped carbon), which have led to significant improvements in selectivity towards specific diols such as 1,2-propanediol (1,2-PD), 1,3-propanediol (1,3-PD), and ethylene glycol (EG). While substantial progress in mechanistic understanding and catalyst performance has been achieved, challenges persist regarding catalyst stability under harsh hydrothermal conditions, the economic viability of noble metal systems, and the processing of complex polyol mixtures from lignocellulosic hydrolysates. Future directions for this field underscore the imperative for more robust, cost-effective catalysts, advanced computational tools, and intensified process designs to facilitate industrial-scale production of bio-based diols. Full article

The interfacial Dzyaloshinskii–Moriya interaction (DMI) plays a pivotal role in stabilising and controlling the motion of chiral spin textures, such as Néel-type bubble domains, in ultrathin magnetic films—an essential feature for next-generation spintronic devices. In this work, we investigate domain wall (DW) dynamics in magnetron-sputtered Ta(3 nm)/Pt(3 nm)/Co(1 nm)/RuO₂(1 nm) [Ru(1 nm)]/Pt(3 nm) multilayers, benchmarking their behaviour against control stacks. Vibrating sample magnetometry (VSM) was employed to determine saturation magnetisation and perpendicular magnetic anisotropy (PMA), while polar magneto-optical Kerr effect (P-MOKE) measurements provided coercivity data. Kerr microscopy visualised the expansion of bubble-shaped domains under combined perpendicular and in-plane magnetic fields, enabling the extraction of effective DMI fields. Brillouin light scattering (BLS) spectroscopy quantified the asymmetric propagation of spin waves, and micromagnetic simulations corroborated the experimental findings. The Pt/Co/RuO₂ system exhibits a Dzyaloshinskii–Moriya interaction (DMI) constant of ≈1.08 mJ/m², slightly higher than the Pt/Co/Ru system (≈1.03 mJ/m²) and much higher than the Pt/Co control (≈0.23 mJ/m²). Correspondingly, domain walls in the RuO₂-capped films show pronounced velocity asymmetry under in-plane fields, whereas the symmetric Pt/Co/Pt shows negligible asymmetry. Despite lower depinning fields in the Ru-capped sample, its domain walls move faster than those in the RuO₂-capped sample, indicating reduced pinning. Our results demonstrate that integrating RuO₂ significantly alters interfacial spin–orbit interactions. Full article

Industrial catalysts are accelerating the global transition toward renewable energy, serving as enablers for innovative technologies that enhance efficiency, lower costs, and improve environmental sustainability. This review explores the pivotal roles of industrial catalysts in hydrogen production, biofuel generation, and biomass conversion, highlighting their transformative impact on renewable energy systems. Precious-metal-based electrocatalysts such as ruthenium (Ru), iridium (Ir), and platinum (Pt) demonstrate high efficiency but face challenges due to their cost and stability. Alternatives like nickel-cobalt oxide (NiCo₂O₄) and Ti₃C₂ MXene materials show promise in addressing these limitations, enabling cost-effective and scalable hydrogen production. Additionally, nickel-based catalysts supported on alumina optimize SMR, reducing coke formation and improving efficiency. In biofuel production, heterogeneous catalysts play a crucial role in converting biomass into valuable fuels. Co-based bimetallic catalysts enhance hydrodeoxygenation (HDO) processes, improving the yield of biofuels like dimethylfuran (DMF) and γ-valerolactone (GVL). Innovative materials such as biochar, red mud, and metal–organic frameworks (MOFs) facilitate sustainable waste-to-fuel conversion and biodiesel production, offering environmental and economic benefits. Power-to-X technologies, which convert renewable electricity into chemical energy carriers like hydrogen and synthetic fuels, rely on advanced catalysts to improve reaction rates, selectivity, and energy efficiency. Innovations in non-precious metal catalysts, nanostructured materials, and defect-engineered catalysts provide solutions for sustainable energy systems. These advancements promise to enhance efficiency, reduce environmental footprints, and ensure the viability of renewable energy technologies. Full article

Single-atom catalysts (SACs) have emerged as highly promising catalytic materials for the hydrogen evolution reaction (HER), attributed to their maximal atomic utilization efficiency and unique electronic configurations. Many structure parameters can influence the catalytic performance of SACs for HER, and the intrinsic advantages of SACs for HER still need to be summarized. This review systematically summarizes recent advances in SACs for HER. It discusses various types of SACs (including those based on Pt, Co, Ru, Ni, Cu, and other metals) applied in HER, and elaborates the critical factors influencing catalytic performance—specifically, the supports, coordination environments, and synergistic effects of these SACs. Furthermore, current research challenges and future perspectives in this rapidly developing field are also outlined. Full article

This study examines the surface chemistry of platinum, palladium, rhodium, and ruthenium-substituted lanthanum strontium cobaltate perovskite catalysts in the context of the dry reforming of methane (DRM). The catalysts were synthesized by the solution combustion method and characterized by using a series of techniques. To explore the effect of noble metal ion substitution on the DRM, surface reaction was probed by CH₄/CO₂ TPSR using mass spectroscopy. It was recognized that La_1−xSr_xCo_1−yPd_yO₃ show the best activities for the reaction in terms of the temperature but became deactivated over time. CH₄/CO₂ temperature-programmed surface reactions (TPSRs) were set up to unravel the details of the surface phenomena responsible for the deactivation of the DRM activity on the LSPdCO. The CH₄/CO₂ TPSR analysis conclusively demonstrated the importance of lattice oxygen in the removal of carbon, which is responsible for the stability of the catalysts on the synthesized perovskites upon noble metal ion substitution. Full article

We investigated a novel natural dye-sensitized solar cell (DSSC) utilizing gadolinium ruthenate pyrochlore oxide Gd₂Ru₂O₇ (GRO) as a photoanode and compared its performance to the TiO₂-Gd₂Ru₂O₇ (TGRO) combined-layer configuration. The films were fabricated using the spin-coating technique, resulting in spherical grains with an estimated mean diameter of 0.2 µm, as observed via scanning electron microscopy (SEM). This innovative photoactive gadolinium ruthenate pyrochlore oxide demonstrated strong absorption in the visible range and excellent dye adhesion after just one hour of exposure to natural dye. X-ray diffraction confirmed the presence of the pyrochlore phase, where Raman spectroscopy identified various vibration modes characteristic of the pyrochlore structure. Incorporating Gd₂Ru₂O₇ as the photoanode significantly enhanced the overall efficiency of the DSSCs. The device configuration FTO/compact-layer/Gd₂Ru₂O₇/Hibiscus-sabdariffa/electrolyte(I⁻/I₃⁻)/Pt achieved a high efficiency of 9.65%, an open-circuit voltage (Voc) of approximately 3.82 V, and a current density of 4.35 mA/cm² for an active surface area of 0.38 cm². A mesoporous TiO₂-based DSSC was fabricated under the same conditions for comparison. Using impedance spectroscopy and cyclic voltammetry measurements, we provided evidence of the mechanism of conductivity and the charge carrier’s contribution or defect contributions in the DSSC cells to explain the obtained Voc value. Through cyclic voltammetry measurements, we highlight the redox activities of hibiscus dye and electrolyte (I⁻/I₃⁻), which confirmed electrochemical processes in addition to a photovoltaic response. The high and unusual obtained Voc value was also attributed to the presence in the photoanode of active dipoles, the layer thickness, dye concentration, and the nature of the electrolyte. Full article

Developing efficient and durable electrocatalysts for the alkaline hydrogen evolution reaction (HER) is crucial for sustainable hydrogen production. Herein, we report a novel RuP₂/Mn₂P₂O₇ heterojunction anchored on a three-dimensional nitrogen and phosphorus co-doped porous carbon (RuP₂/Mn₂P₂O₇/NPC) framework as a high-performance HER catalyst, synthesized via a controlled pyrolysis–phosphidation strategy. The heterostructure achieves uniform dispersion of ultrafine RuP₂/Mn₂P₂O₇ heterojunctions with well-defined interfaces. Furthermore, phosphorus doping restructures the electronic configuration of Mn and Ru species at the RuP₂/Mn₂P₂O₇ heterointerface, enabling enhanced catalytic activity through the accelerated electron transfer and kinetics of the HER. This RuP₂/Mn₂P₂O₇/NPC catalyst exhibits exceptional HER activity with 1 M KOH, requiring only 69 mV of overpotential to deliver 10 mA·cm⁻² and displaying a small Tafel slope of 69 mV·dec⁻¹, rivaling commercial 20% Pt/C. Stability tests reveal negligible activity loss over 48 h, underscoring the robustness of the heterostructure. The RuP₂/Mn₂P₂O₇ heterojunction demonstrates markedly reduced overpotentials for the electrochemical HER process, highlighting its enhanced catalytic efficiency and improved cost-effectiveness compared to the conventional catalytic systems. This work establishes a strategy for designing a transition metal phosphide heterostructure through interfacial electronic modulation, offering broad implications for energy conversion technologies. Full article

The composition of platinum group minerals localized in sulfide droplets from peridotites of the Zhelos intrusion was studied on a scanning electron microscope and on an electron probe microanalyzer. As part of this study, also an analytical approach based on the variation in accelerating voltage, electron beam intensity and probe diameter is considered in order to estimate the X-ray generation region, when analyzing PGM microinclusions comparable in size to the radiation generation region or smaller. Estimates were made of the possibility of reducing the size of the local analysis area when the accelerating voltage was reduced. The influence of the matrix composition on the results of the local analysis of PGM microphases and accuracy of the Pd and Pt content determination was also evaluated. The findings of the experiments conducted allowed for the successful identification of elements belonging to the PGM microphases and the host matrix. This approach enabled the estimation of the precise levels of impurity elements in their composition. Using a scanning electron microscope in the automatic scanning mode for the detection of heavy elements, 10 single and composite grains of three platinum group minerals larger than 5 µm and 22 microphases ranging in size from 0.3 to 4 µm were detected in the sulfide droplets. The large phases are merenskyite, omeiite and michenerite, with merenskyite being predominant. Among the microscopic inclusions were identified Pd-Bi-Te, Os-Ru-As and Rh-As-S phases. The composition of the studied palladium bismuthotelluride samples indicates a formation temperature range of 489–700 °C. Full article

Over the last nine decades, 2,2′:6′,2″-terpyridine (terpy) derivatives and their transition d-metal complexes have been extensively explored due to their unique and widely tuned optical, electrochemical, and biological properties. Terpyridyl transition metal complexes occupy a prominent position among functional molecular materials for applications in optoelectronics, life science, catalysis, and photocatalysis, as well as they have played a key role in determining structure–property relationships. This review summarizes the developments of amine-functionalized R-C₆H₄-terpy systems and their d-metal complexes, largely concentrating on their photophysical and electrochemical properties. Functionalization of the terpy core with the electron-rich group, attached to the central pyridine ring of the terpy backbone via the phenylene linker, gives rise to organic push–pull systems showing the photoinduced charge flow process from the peripheral donor substituent to the terpy acceptor. The introduction of amine-functionalized R-C₆H₄-terpy systems into the coordination sphere of a d-metal ion offers an additional way for controlling the photophysics of these systems, in agreement with the formation of the excited state of intraligand charge transfer (ILCT) nature. Within this review, a detailed discussion has been presented for R-C₆H₄-terpys modified with acyclic and cyclic amine groups and their Cr(III), Mn(I), Re(I), Fe(II), Ru(II), Os(II), Pt(II), and Zn(II) coordination compounds. Full article

The electrocatalytic hydrogenation (ECH) of biomass-derived phenolic compounds is a promising approach to the production of value-added chemicals and biofuels in a sustainable way under moderate reaction conditions. This study provides a comprehensive comparison of electrochemical and thermochemical hydrogenation processes, highlighting their relative advantages in terms of energy efficiency, product selectivity, and environmental impact. Several electrocatalysts (Pt, Pd, Rh, Ru), membranes (Nafion, Fumasep, GO-based PEMs), and reactor configurations are tested for the selective conversion of model compounds such as phenol, guaiacol, furfural, and levulinic acid. The contributions made by the electrode material, electrolyte composition, membrane nature, and reaction conditions are critically evaluated in relation to Faradaic efficiency, conversion rates, and product selectivity. The enhancement in the performance achieved by a new catalyst architecture is emphasized, such as MOF-based systems and bimetallic/trimetallic catalysts. In addition, a demonstration of graphite-based membranes and membrane-separated slurry reactors (SSERs) is provided, for enhanced ion transport and reaction control. The results illustrate the potential of using ECH as a low-carbon, scalable, and tunable method for the upgrading of biomass. This study offers valuable insights and guidelines for the rational design of next-generation electrocatalytic systems toward green chemical synthesis and emphasizes promising perspectives for the strategic development of electrochemical technologies in the pathway of a sustainable energy economy. Full article